Radiometric Dating of Mississippi Valley-type Ore Deposits Utilizing U-Pb and Th-Pb for Hydrothermal Calcite and Rb-Sr for Sphalerite

利用 U-Pb 和 Th-Pb 测定热液方解石和 Rb-Sr 测定闪锌矿的辐射测年法对密西西比河谷型矿床进行放射性测年

• 批准号: 9614264
• 负责人: Joyce Brannon
• 金额: $ 19万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-01-01 至 1999-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9614264&HistoricalAwards=false
• 关键词: Radiometric; Dating; Mississippi; Valley; type

9614264 Brannon The proposed work seeks to improve on the isotopic methodology for dating ore-stage mineralization in Mississipi Valley-type (MVT) Pb-Zn deposits in order to provide necessary constraints for understanding the mechanisms of ore formation. The proposed study will concentrate on: (1) the radiometric dating of two North American MVT ore deposits (Illinois-Kentucky-Fluorspar and Pine-Point Zn-Pb deposits) for which conflicting ages of ore formation exist at the moment; (2) dating of ore-stage calcite and sphalerite from mines of the Tri-State (Missouri, Kansas, Oklahoma) MVT district; and (3) dating two Proterozoic MVT deposits in South Africa, thought to be among the oldest deposits of this type currently known. In addition to dating, the Rb-Sr and U-Th-Pb isotopic systematics will be used as tracers of the ore-forming fluids. Information on the source of fluids is necessary to assess models of ore genesis in the various localities and to construct a better genetic model for MVT's worldwide.

小行星9614264 拟议的工作旨在改善密西西比河谷型（MVT）铅锌矿床的同位素定年成矿作用的方法，以提供必要的限制，了解成矿机制。 拟议的研究将集中在：（1）北美两个MVT矿床的放射性测年（伊利诺斯州-肯塔基州-萤石和松点锌铅矿床），目前存在相互冲突的成矿年龄;（2）三州矿山矿石阶段方解石和闪锌矿的定年（密苏里州、堪萨斯、俄克拉荷马州）MVT区;（3）测定了南非两个元古代MVT矿床的年龄，认为这是目前已知的最古老的此类矿床。 除定年外，Rb-Sr和U-Th-Pb同位素体系也将被用作成矿流体的示踪剂。 流体来源的信息是必要的，以评估模型的矿石成因在不同的地方，并建立一个更好的遗传模型MVT的世界各地。